Comparison of dust emissions, transport, and deposition between the Taklimakan Desert and Gobi Desert from 2007 to 2011
Comparison of dust emissions, transport, and deposition between the Taklimakan Desert and Gobi Desert from 2007 to 2011
复制标题
2007-2011年塔克拉玛干沙漠与戈壁沙漠沙尘排放、输送和沉降对比
DOI：
10.1007/s11430-016-9051-0
复制
发表时间：
2017-07-01
影响因子：
5.7
通讯作者：
Xie, TingTing
中科院分区：
文献类型：
--
作者：
Chen, SiYu;Huang, JianPing;Xie, TingTing
塔克拉玛干沙漠(TD)和戈壁沙漠(GD)是东亚地区最重要的两个沙尘源，对区域乃至全球的能源收支、生态系统和水循环具有重要影响。为了研究TD和GD对整个东亚沙尘浓度的贡献，基于WRF-CHEM天气研究和预报模式，系统地比较了2007-2011年不同季节TD和GD的沙尘排放、输送和沉积。由于地形、海拔、热力条件和大气环流的不同，这两个沙尘源区的扬尘、扬起和远距离输送明显不同。具体地说，广东的地形相对平坦，海拔较高，该地区受到高海拔两股急流的影响，导致高空大气风速较高。深厚的对流混合使急流下降支持续向下输送动量至对流层中层，导致对流层低层风速增强，有利于广东沙尘粒子的垂直抬升。因此，广东沙尘很可能是在强西风急流的作用下输送的，因此对东亚沙尘浓度的贡献最大。春季和夏季，广东省排放的沙尘中，约有35%和31%分别输送到东亚偏远地区。TD的扬尘能力是东亚最高的，春季的排放量约为70.54TgYr(-1)，占东亚沙尘排放总量的42%。然而，TD位于塔里木盆地，三面环山。此外，地面风向以东风为主，高海拔地区的平均风速相对较小。结果表明，TD尘埃粒子不容易运移到塔里木盆地以外，大部分尘埃粒子在隆升后重新沉积，总沉积速率约为40gm(-2)。只有当TD尘埃粒子上升到4公里以上，并夹带到西风带时，它们才开始进行远距离输送。因此，TD沙尘对东亚沙尘浓度的贡献相对较小。春季和夏季分别只有25%和23%的TD沙尘输送到东亚的偏远地区。
The Taklimakan Desert (TD) and Gobi Desert (GD) are two of the most important dust sources in East Asia, and have important impact on energy budgets, ecosystems and water cycles at regional and even global scales. To investigate the contribution of the TD and the GD to dust concentrations in East Asia as a whole, dust emissions, transport, and deposition over the TD and the GD in different seasons from 2007 to 2011 were systematically compared, based on the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem). Dust emissions, uplift, and long-range transport related to these two dust source regions were markedly different due to differences in topography, elevation, thermal conditions, and atmospheric circulation. Specifically, the topography of the GD is relatively flat, and at a high elevation, and the area is under the influence of two jet streams at high altitudes, resulting in high wind speeds in the upper atmosphere. Deep convective mixing enables the descending branch of jet streams to continuously transport momentum downward to the mid-troposphere, leading to enhanced wind speeds in the lower troposphere over the GD which favors the vertical uplift of the GD dust particles. Therefore, the GD dust was very likely to be transported under the effect of strong westerly jets, and thus played the most important role in contributing to dust concentrations in East Asia. Approximately 35% and 31% of dust emitted from the GD transported to remote areas in East Asia in spring and summer, respectively. The TD has the highest dust emission capabilities in East Asia, with emissions of about 70.54 Tg yr(-1) in spring, accounting for 42% of the total dust emissions in East Asia. However, the TD is located in the Tarim Basin and surrounded by mountains on three sides. Furthermore, the dominant surface wind direction is eastward and the average wind speed at high altitudes is relatively small over the TD. As a result, the TD dust particles are not easily transported outside the Tarim Basin, such that most of the dust particles are re-deposited after uplift, at a total deposition rate of about 40 g m(-2). It is only when the TD dust particles are uplifted above 4 km, and entrained in westerlies that they begin to undergo a long-range transport. Therefore, the contribution of the TD dust to East Asian dust concentrations was relatively small. Only 25% and 23% of the TD dust was transported to remote areas over East Asia in spring and summer, respectively.